Reallocated Sector Count Slowly Increasing

[BostonDan]

I've have a hard drive in one of my NAS's that has been exhibiting increases in the reallocated sector count for about 2 years now. Every few days, the reallocated sector count increases by 1. I purchased a spare drive 2 years ago after the 1st reallocated sector, expecting the drive to fail, but it is still handing in there. It's currently up to 544 reallocated sectors.

Is there any magic reallocated sector count number that when reached I should go ahead and swap in the new drive?

Are there any issues with continuing to wait for a full drive failure?

Appreciate your thoughts. - BostonDan

 

[microchip]

According to wikipedia

Count of reallocated sectors. When the hard drive finds a read/write/verification error, it marks that sector as "reallocated" and transfers data to a special reserved area (spare area). This process is also known as remapping, and reallocated sectors are called "remaps". The raw value normally represents a count of the bad sectors that have been found and remapped. Thus, the higher the attribute value, the more sectors the drive has had to reallocate. This allows a drive with bad sectors to continue operation; however, a drive which has had any reallocations at all is significantly more likely to fail in the near future.[3] While primarily used as a metric of the life expectancy of the drive, this number also affects performance. As the count of reallocated sectors increases, the read/write speed tends to become worse because the drive head is forced to seek to the reserved area whenever a remap is accessed. If sequential access speed is critical, the remapped sectors can be manually marked as bad blocks in the file system in order to prevent their use.

I've had a drive which gave up the ghost at 100 while another one gave up the ghost at 250. I don't think there's a publicly known value that indicates drive failure. At least I don't know any.

 

[thiggins]

You have the drive. I'd just swap it in, after, of course, making sure your backup is in order.